Ten years ago today, we lost Space Shuttle Columbia and her crew. Here, Apollo 11 astronaut Buzz Aldrin salutes as NASA Administrator Charles Bolden looks on, during a wreath laying ceremony held in the crew's memory today at Arlington National Cemetery. A public memorial service was also held at Kennedy Space Center in Florida.

Today has been a day of remembrance. Not just for the Agency, or for America, but for anyone who has ever been inspired by the ongoing quest of space exploration. To Rick Husband, William McCool, David Brown, Laurel Clark, Michael Anderson, Ilan Ramon, Kalpana Chawla, and to all those who have given their lives in the pursuit of that quest, we say thank you. You are not forgotten. And it is in your memory that we continue to dare mighty things.